Plastic bobbin carrier

ABSTRACT

A plastic bobbin carrier for taking up threads and yarns, with a cylindrical or conical shell provided with radial openings and with one end ring at each end of the shell, whereby this shell is comprised of several cylindrical or conical shell segments. These shell segments form a joint cylindrical or conical inner shell surface. Supporting webs join these shell segments together. These supporting webs run in a straight line or helicoidally from one end ring to the other, resting on the inner surfaces of the shell segments to which they are joined as one piece. The supporting webs may be rigid or ductile. When ductile supporting webs are employed, axial, radial, or axial and radial compressibility of the bobbin carrier in attainable.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention concerns a plastic bobbin carrier for taking up threadsand yarns, with a cylindrical or conical shell which is provided withradial openings and which forms a winding surface and with one end ringat each end of the shell, whereby the shell is comprised of severalshell segments configured at a distance from one another, forming acylindrical or conical inner shell surface, said segments being joinedtogether by supporting webs.

2. Description of the Prior Art

A known bobbin carrier of this type (DE 24 08 949 A1) incorporatesintermediate rings between two end rings, whereby these intermediaterings are positioned parallel to the end rings and are axially displacedfrom one another, and webs parallel to the axis are located between theintermediate rings for the purpose of connecting adjacent intermediaterings. The webs are provided with bending points which facilitatebending radially to the axis, thereby enabling axial shortening of thebobbin carrier.

In the case of this known bobbin carrier, the fact that sufficient spacemust remain between the rings for the webs after axial compression ofthe bobbin carrier results in a minimum permissible limit for thespacing between the rings. Several mould segments are required in themanufacture of this known bobbin carrier, and each of these segments isindividually drawn in radial direction during removal from the mould.This inevitably results in all the webs produced from such a mouldsegment being unmoulded in the same direction of pull and their flanksbeing formed accordingly. As a result, the cross-sections of adjacentwebs will differ, unless an economically inviable number of mouldsegments is employed. This bobbin carrier therefore possesses divergentwebs over its circumference which may differ, for example, with regardto their flexural strength.

Furthermore, on this known bobbin carrier the webs which engage with aring are displaced in relation to one another in the circumferentialdirection. When axial compression is applied, this results indeformation of the rings concerned, which may well be undesired.

A further bobbin carrier is known (DE-PS 1 635 084) which has proved tobe generally effective in the wet treatment of threads and yarns,incorporating ring elements between the end rings on the faces of thebobbin carrier, with connecting webs running primarily in the axialdirection between these ring elements. In conjunction with the ringelements, the connecting webs form a winding surface on which the innerlayers of a lap of thread or yarn are supported. The inner windings ofsuch laps thus rest both on the ring elements and on the outer edges ofthe connecting webs which protrude into the winding surface, whereby theindividual ring elements are to be regarded as rigid elements.

In the case of this known bobbin carrier, the fact that the innerwindings of the lap come into direct contact with the connecting webs,which deform and alter their distances from the adjacent ring elementsduring compression, may result in the inner windings of the yarnbecoming caught between two sections of a connecting element, or betweena connecting element and an adjacent ring element. In this way, theinner windings are occasionally destroyed and cannot be unwound in thecorrect manner. Furthermore, a multipart mould is required in themanufacture of this known bobbin carrier, in order to ensure therequired radial extension of the cross-section of the carrying elements.

SUMMARY OF THE INVENTION

The present invention is based on the task of further developing abobbin carrier of the type mentioned at the beginning of thisdescription, in particular so as to simplify the method of manufactureand to reduce the required scope of complexity regarding the mould.

This objective is attained by a bobbin carrier of the type mentioned atthe beginning of this description by virtue of the fact that thesupporting webs are continuous webs running in a straight line orhelicoidally from one end ring to the other, that these webs possess across-section which is constant over their entire length or diminishesin one direction, that they rest on the inner surfaces of the shellsegments, to which they are joined as one piece, and that they protruderadially over the radially inwardmost surface of at least one end ring.

The mould for production of such a bobbin carrier requires only twoouter mould parts and a core, whereby the latter can be produced as aone-piece core and can be drawn towards one end of the mould; forhelicoidal supporting webs, rotation of the core is additionallynecessary.

The shell segments can be provided with perforations in the establishedmanner. The surfaces of the shell segments can additionally be providedwith a toughened or corrugated finish.

The bobbin carrier in accordance with the present invention can furtherbe configured in such a manner that the sections of the supporting webslocated between two shell segments are ductile.

This configuration permits axial and/or radial compression of the bobbincarrier, enabling laps positioned one over the other along the axis tobe pressed together, or a reduction in the circumference for shrinkingyarn. This bobbin carrier is subsequently also suitable for the dyeingand thermal treatment of yarns.

The configuration of the supporting webs in accordance with the presentinvention eliminates the possibility of the webs coming into contactwith the yarn. Consequently, buckling or bending of the supporting websin the course of axial or radial compression can never lead to threadsor yarns becoming caught on adjacent shell segments.

The bobbin carrier in accordance with the present invention can furtherbe configured in such a manner that the spaces between the shellsegments are partially closed by a film covering in the area of theinner surface of the shell. This film covering enables the area of theopenings, which is otherwise determined primarily by the distancesbetween the shell segments, to be reduced to the desired size, wherebythe size of the opening left by the film covering may vary over theheight of the bobbin carrier.

The bobbin carrier in accordance with the present invention can furtherbe configured in such a manner that the film covering is contoured onits radially outward-facing side and incorporates zones of reducedflexural strength. In this way it can be ensured that the film coveringalways bends radially inwards and never outwards during compression.

The bobbin carrier in accordance with the present invention can furtherbe configured in such a manner that the shell segments are parallelrings, the axes of which coincide with the longitudinal axis of thebobbin carrier. The shell surface bearing the yarn lap is thendetermined solely by the rings which move towards one another underaxial compression, but which cannot come into direct contact with oneanother on account of the supporting webs provided on the inside.

The bobbin carrier in accordance with the present invention can furtherbe configured in such a manner that the shell segments are constitutedby the windings of at least one supporting web running spirally from oneend ring to the other.

The bobbin carrier in accordance with the present invention can furtherbe configured in such a manner that the shell segments are bearing unitswhich are located at a distance from one another in the circumferentialdirection and which mesh together, leaving a gap in the circumferentialdirection, whereby the supporting webs are located on the inner surfacesof the bearing units, in the area of the meshing parts of the bearingunits. In this manner, the carrier in accordance with the presentinvention can also be configured in such a manner that it is radiallycompressible, thereby enabling it to adapt to the shrinkage of thespooled yarn which is likely to occur in particular when the yarn issubjected to thermal treatment.

The bobbin carrier in accordance with the present invention can furtherbe configured in such a manner that it is compressible in the axialdirection only, in the radial direction only, or in the axial and radialdirections. For each type of compression, cams can be provided inaddition to the supporting webs, to ensure that the desired distance ismaintained between adjacent shell segments.

The bobbin carrier in accordance with the present invention can furtherbe configured in such a manner that each supporting element runscontinuously from one end ring to the other, whereby these supportingelements can be provided with perforations. This will be necessary inparticular when only a small number of supporting elements are used,which will subsequently possess a relatively high degree ofcircumferential extension.

The bobbin carrier in accordance with the present invention can furtherbe configured in such a manner that the supporting elements are dividedin the axial direction into several spaced sub-elements which areconnected by supporting webs. Such a bobbin carrier is compressible inboth the axial and radial directions.

The bobbin carrier in accordance with the present invention can furtherbe configured in such a manner that the shell segments incorporaterecesses on their mutually facing edges in the area in which asupporting web passes through. In this way, the length of the ductilesupporting webs between two adjacent shell segments can be increased.This may be expedient, in order to attain the desired compression inconjunction with the required cross-sectional dimensions for thesupporting webs.

The bobbin carrier in accordance with the present invention can furtherbe configured in such a manner that the spacing between the shellsegments increases and/or decreases as the distance from an end ringincreases. This can help to even out the cross-section of the openingfor a dye bath or similar.

BRIEF DESCRIPTION OF THE DRAWINGS

Some embodiments of the bobbin carrier in accordance with the presentinvention are described below with reference to drawings.

FIG. 1 shows an initial embodiment of the bobbin carrier in accordancewith the present invention, whereby the shell segments take the form ofrings; an axial section is shown on the left and a side view on theright.

FIG. 2 shows a view in the direction of arrow 2 in FIG. 1 in the tophalf, and a section along the line 2--2 in FIG. 1 in the bottom half.

FIG. 3 shows the carrier in accordance with FIG. 1 in an axiallycompressed state.

FIG. 4 shows a bobbin carrier similar to that shown in FIGS. 1 to 3 withspiral supporting webs.

FIG. 5 shows a further embodiment of the bobbin carrier in accordancewith the present invention, whereby the shell segments are formed by thewindings of spiral supporting elements.

FIG. 6 shows a radially compressible embodiment of the bobbin carrier inaccordance with the present invention, whereby the shell segments takethe form of a shell running from one end ring to the other.

FIG. 7 shows a detailed view of two adjacent rings and one connectingsupporting web.

FIG. 7A is a cross-sectional view taken along line 7A--7A of FIG. 7.

FIG. 8 shows a detailed view in accordance with FIG. 7 in an axiallycompressed state.

FIG. 8A is a cross-sectional view taken along line 8A--8A of FIG. 8.

FIG. 9 shows a detailed cross-section through two rings positioned oneabove the other and a connecting film covering contoured on its outerside.

FIG. 10 shows another embodiment of the bobbin carrier in accordancewith the present invention, similar to FIG. 1, but wherein the webs havea cross-section of circumferentially diminishing cross-section from topto bottom.

FIG. 11 shows a view in the direction of arrow 11 in FIG. 10 in the tophalf, and a section along line 11--11 in the bottom half.

FIG. 12 shows still another embodiment of the bobbin carrier inaccordance with the present invention, similar to FIG. 1, but whereinthe webs have a cross-section of both circumferentially and radiallydiminishing cross-section from top to bottom.

FIG. 13 shows a view in the direction of arrow 13 in FIG. 12 in the tophalf, and a section along line 13--13 in the bottom half.

FIG. 14 shows another embodiment of the bobbin carrier in accordancewith the present invention, similar to FIG. 1, but wherein the spacingbetween the shell segments increases as the distance from both the firstand second end rings increases.

FIG. 15 shows still another embodiment of the bobbin carrier inaccordance with the present invention, similar to FIG. 1, but whereinthe spacing between the shell segments decreases as the distance fromboth the first and second end rings increases.

FIG. 16 shows another embodiment of the bobbin carrier in accordancewith the present invention, similar to FIG. 1, but wherein the spacingbetween the shell segments increases as the distance from the first endrings increases.

FIG. 17 shows another embodiment of the bobbin carrier in accordancewith the present invention, similar to FIG. 1, but wherein the spacingbetween the shell segments decreases as the distance from the first endring increases.

DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

The bobbin carrier in accordance with the embodiment shown in FIGS. 1 to3 has one lower end ring, 1, and one upper end ring, 2. The upper endring is provided with an axially protruding collar, 3, of reducedexternal diameter. The collar, 3, of this bobbin carrier fits into thelower end ring, 1, of an identical bobbin carrier which is placed overthe collar. Between end rings 1 and 2, co-axial shell segments runningparallel to the end rings are provided in the form of rings, 4, wherebyeach ring, 4, is positioned at a distance from its adjacent ring and/orthe adjacent end ring, 1, 2. The distances between these rings may varyover the height of the bobbin carrier.

In this embodiment, the end rings, 1, 2, and the rings, 4, form acylindrical winding surface, 5. The inner surfaces of the end rings, 1,2 and 4, form a joint cylindrical inner shell surface, above which onlythe collar, 3, protrudes radially inwards.

Supporting webs, 6, are provided which run in a straight line from theupper end ring, 2, at the point of connection with the collar, 3, to thelower end ring, 1, and these webs, 6, are fixed to the inner surfaces ofthe rings. The supporting webs, 6, possess the same cross-section alongtheir entire length. A reduction in the cross-section in the directionof the lower end ring, 1, would also be possible, however, as shown withrespect to webs 6' in FIGS. 10 and 11 and webs 6" in FIGS. 12 and 13.

The annular gaps between the lower end ring, 1, and the adjacent ring,4, between adjacent rings, 4, and between the uppermost ring, 4, and theupper end ring, 2, are partially covered by a film covering, 7. Theextent of this covering determines the opening of the bobbin carrier,which may be required for a dye bath, for example.

As shown in FIG. 9, the film covering, 7, can be contoured in such amanner that it is thinnest in the middle of the annular gap. In thisway, a folding point is created for the film covering, 7, which causesthe film covering, 7, to fold radially inwards when the bobbin carrieris subjected to axial compression. In the embodiment shown, the filmcovering, 7, is contoured on its outer surface.

The lower end ring, 1, is comprised of two sub-rings, 8, 9, which arejoined together by means of rigid support webs, 10, which leaveopenings, 11, between the two sub-rings.

FIGS. 7 and 7A show two adjacent rings, 4, to which cross-shapedelevations or recesses, 30, have been applied, which are intended tosecure the yarn on the winding surface. The space between the two rings,4, is partially closed by a film covering, 7, leaving openings, 31.

The rings, 4, are provided with recesses, 32, in the area in which therings, 4, are connected to the supporting web, 6. These recesses betweenadjacent rings, 4, increase the ductile span of the supporting web, 6.They thus improve the ductility.

FIGS. 8 and 8A show the main features of the view in accordance withFIGS. 7 and 7A after axial compression, whereby the deformed supportingweb, 6, determines the axial compressibility of the bobbin carrier.

In the above-described embodiment and all the embodiments describedbelow, the bobbin carrier in accordance with the present invention ismoulded as a single piece in plastic.

The injection mould for this bobbin carrier is provided by a core (notshown) which can be drawn out of the lower end ring, 1. Only two mouldhalves are required for the outer mould.

FIG. 4 shows a further embodiment of the bobbin carrier in accordancewith the present invention, incorporating a lower end ring, 12, and anupper end ring, 13, whereby the latter has an axially protruding collar,14, of reduced external diameter, incorporating a reserve thread groove,15. Here again, spaced rings, 16, are provided between the two endrings, 12, 13, as described with regard to the embodiment shown in FIGS.1 to 3. Supporting webs, 16', are provided which extend helicoidallyfrom the upper end ring, 13, at the joint with the collar, 14, to thelower end ring, 12.

The core required in the manufacture of this bobbin carrier can be drawnout of the lower end ring, 12, whereby a rotary movement correspondingto the helicoidal form of the supporting webs, 16', is to besuperimposed over the straight drawing movement. Two mould halves arerequired for the outer mould, as described above.

The embodiment of the inventive bobbin carrier in accordance with FIG. 5differs from that shown in FIGS. 1 to 3 only in that the shell segmentsare formed by the windings, 17, of two supporting elements extendingspirally between a lower end ring, 18, and an upper end ring, 19.Supporting webs, 20, are provided which extend in the above-describedmanner between the end rings, 18, 19, and are fixed to the innersurfaces of the windings, 17.

The embodiment of the bobbin carrier in accordance with the presentinvention shown in FIG. 6 has a lower end ring, 21 and an upper endring, 22. The upper end ring, 22, incorporates a reserve thread groove,23. All the inner surfaces of the end rings, 21, 22 rest against acommon cylindrical inner surface, 24. Continuous, perforated, shell-typesupport elements, 25, extend between the end rings, 21, 22. The innersurfaces of these support elements, 25, rest against the cylindricalinner surface, 24. Correspondingly, the outer surfaces of the supportelements, 25, and the outer surfaces of the end rings, 21, 22, also lieon a common cylindrical surface and form a winding surface.

There is a zig-zag gap, 26, between each two circumferentially adjacentsupport elements, 25, located between the end rings, 21, 22. The edgesof the support elements, 25, adjoining this gap, 26, on either side thusinterlock in zig-zag form. One supporting web, 27, running in a straightline from the upper end ring, 22, to the lower end ring, 21, is assignedto each gap, 26, and passes through the longitudinal center of thezig-zag form of the gap, 26, whereby in the axial direction it is fixedalternately to the inner surface of one and then the other supportelement, 25.

This embodiment of the bobbin carrier enables the width of the gap, 26,to be reduced, as a result of which it is possible to reduce thecircumference of the winding surface of the bobbin carrier. In this way,due account can be taken of yarn shrinkage.

The support elements, 25, can be divided into spaced sub-elements in theaxial direction, whereby the gaps between the sub-elements can beconnected by additional supporting webs.

The support elements, 25, are provided with openings, 28.

In the case of all the above-described embodiments, the supporting websextend continuously with a constant or diminishing cross-section fromone end ring to the other, whereby the cross-section of the supportingweb protrudes fully radially inwards over the inner surface of thisother end ring. The supporting webs rest against a cylindrical orconically expanding surface which is formed by the inner surfaces of theshell segments and end rings.

The bobbin carrier in accordance with the present invention can beprovided with diverse designs of end rings. These end rings can beconfigured in such a manner that the end rings of adjacent bobbincarriers axially interlock or, as applies in the case of the embodimentshown in FIG. 6, buffet against one another.

In particular, the outer surfaces of the end rings can form a continuouscylindrical or conical winding surface with the other shell segments. Itis also possible to provide an end ring with a radially protrudingcollar.

The supporting webs can be configured in rigid design, therebypermanently fixing the distance between adjacent shell segments. It ismore expedient, however, to design the supporting webs in such a mannerthat they deform in the area of the gap between the shell segments whenthe bobbin carrier is subjected to axial pressure, resulting in ashortening of the bobbin carrier. In this connection, reference is madeto the embodiments in accordance with FIGS. 1 to 5.

Equally, rigid or circumferentially ductile supporting webs, 27, inaccordance with the embodiment shown in FIG. 6 can be employed, toenable adaption to radial shrinkage.

I claim:
 1. A one-piece plastic bobbin carrier for taking up threads andyarns, said plastic bobbin carrier being in the form of a substantiallycylindrical shell having radial openings therein and first and secondends, said shell comprising:first and second end rings at said first andsecond ends of said shell, said first and second end rings havingradially inwardmost surfaces; an outer winding surface; a substantiallycylindrical inner surface; a plurality of shell segments spaced apartfrom one another, said shell segments having inner and outer surfaces,said outer surfaces defining said outer winding surface of said shell,and said inner surfaces defining said inner surface of said shell; aplurality of supporting webs joining said shell segments together, saidsupporting webs being continuous and extending from said first end ringto said second end ring, said supporting webs having a cross sectionwhich is constant over their entire length, said supporting webs restingon said inner surface of said shell segments and being formed in onepiece with said shell segments, and said supporting webs protrudingradially over said radially inwardmost surface of at least one of saidfirst and second end rings.
 2. The bobbin carrier of claim 1, whereinsaid webs extend axially in a straight line between said first andsecond end rings.
 3. The bobbin carrier of claim 1, wherein said websextend helicoidally between said first and second end rings.
 4. Thebobbin carrier of claim 1, wherein sections of said supporting webslocated between adjacent shell segments are ductile.
 5. The bobbincarrier of claim 1, further comprising a film covering on said innersurface of said shell, said film covering partially closing the spacesbetween said shell segments.
 6. The bobbin carrier of claim 5, whereinsaid film covering has a contoured, radially outwardly facing side andincorporates zones of reduced flexural strength.
 7. The bobbin carrierof claim 1, wherein said bobbin carrier has a longitudinal axis, andwherein said shell segments are parallel rings coaxial with saidlongitudinal axis of said bobbin carrier.
 8. The bobbin carrier of claim1, wherein said shell segments comprise bearing units spacedcircumferentially from one another, said shell segments having opposedside edges and inner and outer surfaces, adjacent side edges of adjacentshell segments being circumferentially spaced from one another andhaving complementary alternating indentations and protrusions, and saidsupporting webs being located on said inner surfaces of said shellsegments at said side edges.
 9. The bobbin carrier of claim 8, whereinsaid bearing units extend continuously between said first and second endrings.
 10. The bobbin carrier of claim 8, wherein said bearing unitscomprise a plurality of spaced axial sub-elements and a plurality ofadditional supporting webs connecting said sub-elements.
 11. The bobbincarrier of claim 1, wherein each said shell segment has opposed sideedges, and said opposed side edges have facing recesses formed thereinin the area where said supporting web rests on said inner surface ofsaid shell segment.
 12. The bobbin carrier of claim 1, wherein thespacing between said shell segments increases as the distance from oneof said first and second end rings increases.
 13. The bobbin carrier ofclaim 1, wherein the spacing between said shell segments increases asthe distance from one of said first and second end rings decreases. 14.A one-piece plastic bobbin carrier for taking up threads and yarns, saidplastic bobbin carrier being in the form of a substantially cylindricalshell having radial openings therein and first and second ends, saidshell comprising:first and second end rings at said first and secondends of said shell, said first and second end rings having radiallyinwardmost surfaces; an outer winding surface; a substantiallycylindrical inner surface; a plurality of shell segments spaced apartfrom one another, said shell segments having inner and outer surfaces,said outer surfaces defining said outer winding surface of said shell,and said inner surfaces defining said inner surface of said shell; aplurality of supporting webs joining said shell segments together, saidsupporting webs being continuous and extending from said first end ringto said second end ring, said supporting webs having a cross sectionwhich diminishes in one direction over their length, said supportingwebs resting on said inner surface of said shell segments and beingformed in one piece with said shell segments, and said supporting websprotruding radially over said radially inwardmost surface of at leastone of said first and second end rings.
 15. A one-piece plastic bobbincarrier for taking up threads and yarns, said plastic bobbin carrierbeing in the form of a substantially cylindrical shell having radialopenings therein and first and second ends, said shell comprising:firstand second end rings at said first and second ends of said shell, saidfirst and second end rings having radially inwardmost surfaces; an outerwinding surface; a substantially cylindrical inner surface; a pluralityof shell segments spaced apart from one another, said shell segmentshaving inner and outer surfaces, said outer surfaces defining said outerwinding surface of said shell, and said inner surfaces defining saidinner surface of said shell; a plurality of supporting webs joining saidshell segments together, said supporting webs being continuous andextending from said first end ring to said second end ring, saidsupporting webs extending helicoidally between said first and second endrings and having a cross section which diminishes in one direction overtheir length, said supporting webs resting on said inner surface of saidshell segments and being formed in one piece with said shell segments,and said supporting webs protruding radially over said radiallyinwardmost surface of at least one of said first and second end rings.16. A one-piece plastic bobbin carrier for taking up threads and yarns,said plastic bobbin carrier being in the form of a substantiallycylindrical shell having radial openings therein and first and secondends, said shell comprising:first and second end rings at said first andsecond ends of said shell, said first and second end rings havingradially inwardmost surfaces; an outer winding surface; a substantiallycylindrical inner surface; a shell segment in the form of a windingextending spirally between said first and second end rings, said windinghaving a plurality of turns spaced apart from one another, said turns ofsaid shell segment having inner and outer surfaces, said outer surfacesdefining said outer winding surface of said shell, and said innersurfaces defining said inner surface of said shell; a plurality ofsupporting webs joining said turns of said shell segment together, saidsupporting webs being continuous and extending from said first end ringto said second end ring, said supporting webs having a cross sectionwhich is constant over their entire length, said supporting webs restingon said inner surface of said turns of said shell segment and beingformed in one piece with said shell segment, and said supporting websprotruding radially over said radially inwardmost surface of at leastone of said first and second end rings.